1. Field of the Invention
The present invention relates to a tailgate operator. More specifically, the invention relates to an electrically-controlled operator for moving a vehicle tailgate between a generally vertical raised position and a generally horizontal lowered position.
2. Related Art
Mechanically and electrically controlled operators for opening vehicle doors are well known. U.S. Pat. No. 1,977,284 to Mathauer discloses a cable actuated door mechanism having an air compressor that provides compressed air to pneumatic cylinders having piston rods connected by flexible cables to doors.
U.S. Pat. No. 2,893,727 to Barnard discloses a power actuated closure including a motor that operates a threaded shaft that is threadedly engaged with an arm connected to a sheave. Operation of the motor causes the arm to be threaded along the shaft, thereby rotating the sheave. The tailgate is rigidly connected to the sheave through a leg, and is raised and lowered as the sheave is rotated by movement of the arm along the shaft. A flexible cable is anchored to the sheave and is wrapped onto the sheave as clockwise rotation of the sheave is initiated. As the cable is wrapped onto the sheave, the sheave pulls downwardly on the cable, thereby opening the tailgate.
U.S. Pat. No. 4,616,444 to Taylor discloses a radio-controlled gate opener having a reversible linear electrical actuator in the form of a screw jack, including an elongated rotary screw connected to an output shaft of a reversible motor pivotally mounted by a bracket and a pivot pin on an arm supported from a gate post. The rotary screw engages a nut pivotally carried on a wrung of the gate, so that rotation of the screw in opposite directions is effective to open and close the gate respectively.
Canadian Pat. No. 969,197 to Rogakos discloses a car tailgate having a bidirectional drive mechanism comprising a motor, a worm gear, and an output member with a pinion gear that meshes with a sector gear. The tailgate is raised and lowered by relative movement between a bracket on a support plate and the sector gear attached to a control arm. Operation of the motor rotates the worm gear, and the worm gear in turn rotates the output member, its pinion gear, and its sector gear, thereby raising or lowering the tailgate.
Netherlands Publication No. 7,407,939 discloses a balancer for a hinged loading gate. The loading gate is pivoted to a vehicle structure hat. A cable is secured at one end to the gate, runs over a pulley, and is connected to a tension spring.
Japanese Publication No. 52-9222 discloses a device for automatically controlling a tailgate of a container transporting vehicle. The tailgate is automatically unlocked as the container is tilted. A hook is rotated, thereby unlocking the tailgate by movement of a first rod connected through a crank, a second rod, and an arm to the container.